This is a request for funds under the Shared Instrument Grant Program to purchase a Becton-Dickinson FACStar plus cell sorter. The instrument will have a dual laser with capability of sorting based on multiparameter analysis of cells including simultaneous DNA and some combination of two immunofluorescences, immunoflurescence and protein, or RNA and immunofluorescence. It will be shared by four major users who are all very experienced with analytical flow cytometry, and use this technique extensively in their research, but do not have cell sorting capability. The requested cell sorter will greatly enhance the progress of their research which encompasses basic cell biology, clinical diagnostic investigation into human bladder cancer and solid tumors, clinical studies of leukemia and effects of chemotherapy, and cellular immunology.